[The Rovering Member]

There is a school of thought that says if a reasonably high mileage autobox has never had a fluid change then it's best to leave it as all the worn friction material is suspended in the fluid & compensating for the actual wear on the components it has come from. Removing it & putting fresh slippery fluid in is likely to allow the worn components to make themselves apparent. Regular fluid changes will of course reduce the wear to a minimum.

I have the same dilemma with our Chrysler Voyager. Nearly 150,000 miles & no problems with the six-speed autobox but there's a chance that the fluid
hasn't been changed.